如何在不点击屏幕的情况下放置对象

1 回答

• 4

  虽然我建议你在用户点击时点击对象并点击屏幕上的点击，但你可以这样做 . （这个例子在Kotlin）

  在开始放置对象之前，需要创建 ModelRenderable . 全局声明一个 @Nullable .

  private var modelRenderable: ModelRenderable? = null
  
  //Create the football renderable
  ModelRenderable.builder()
                  //get the context of the ARFragment and pass the name of your .sfb file
                  .setSource(fragment.context, Uri.parse("FootBall.sfb"))
                  .build()
  
                  //I accepted the CompletableFuture using Async since I created my model on creation of the activity. You could simply use .thenAccept too.
                  //Use the returned modelRenderable and save it to a global variable of the same name
                  .thenAcceptAsync { modelRenderable -> this@MainActivity.modelRenderable = modelRenderable }
  

  编程的主要部分必须在框架的 onUpdate 方法上完成 . 所以你附加了一个像这样的帧更新的监听器

  fragment.arSceneView.scene.addOnUpdateListener(this@MainActivity) //You can do this anywhere. I do it on activity creation post inflating the fragment
  

  现在你处理在侦听器上添加一个对象 .

  override fun onUpdate(frameTime: FrameTime?) {
      //get the frame from the scene for shorthand
      val frame = fragment.arSceneView.arFrame
      if (frame != null) {
          //get the trackables to ensure planes are detected
          val var3 = frame.getUpdatedTrackables(Plane::class.java).iterator()
          while(var3.hasNext()) {
              val plane = var3.next() as Plane
  
              //If a plane has been detected & is being tracked by ARCore
              if (plane.trackingState == TrackingState.TRACKING) {
  
                  //Hide the plane discovery helper animation
                  fragment.planeDiscoveryController.hide()
  
  
                  //Get all added anchors to the frame
                  val iterableAnchor = frame.updatedAnchors.iterator()
  
                  //place the first object only if no previous anchors were added
                  if(!iterableAnchor.hasNext()) {
                      //Perform a hit test at the center of the screen to place an object without tapping
                      val hitTest = frame.hitTest(frame.screenCenter().x, frame.screenCenter().y)
  
                      //iterate through all hits
                      val hitTestIterator = hitTest.iterator()
                      while(hitTestIterator.hasNext()) {
                          val hitResult = hitTestIterator.next()
  
                          //Create an anchor at the plane hit
                          val modelAnchor = plane.createAnchor(hitResult.hitPose)
  
                          //Attach a node to this anchor with the scene as the parent
                          val anchorNode = AnchorNode(modelAnchor)
                          anchorNode.setParent(fragment.arSceneView.scene)
  
                          //create a new TranformableNode that will carry our object
                          val transformableNode = TransformableNode(fragment.transformationSystem)
                          transformableNode.setParent(anchorNode)
                          transformableNode.renderable = this@MainActivity.modelRenderable
  
                          //Alter the real world position to ensure object renders on the table top. Not somewhere inside.
                          transformableNode.worldPosition = Vector3(modelAnchor.pose.tx(),
                                  modelAnchor.pose.compose(Pose.makeTranslation(0f, 0.05f, 0f)).ty(),
                                  modelAnchor.pose.tz())
                      }
                  }
              }
          }
      }
  }
  

  我使用了一种扩展方法

  //A method to find the screen center. This is used while placing objects in the scene
  private fun Frame.screenCenter(): Vector3 {
      val vw = findViewById<View>(android.R.id.content)
      return Vector3(vw.width / 2f, vw.height / 2f, 0f)
  }
  

  这是最终结果
  

  回复于 2024-04-26T13:21:16+08:00